JPH06260572A - Semiconductor device - Google Patents

Abstract

PURPOSE:To improve heat dissipation while the generation of package crack, the increase of cost, and the enlargement of equipment are restrained, by conducting the heat generated from a semiconductor device to a printed board via a metal plate excellent in thermal conductivity. CONSTITUTION:The other surface of a copper plate 7 is coated with adhesive agent excellent in thermal conductivity, and the copper plate 7 of a semiconductor device is bonded to the surface of a printed board 9. Leads 3 are electrically connected with wirings of the printed board 9. The heat generated from a semiconductor element 1 is conducted to the printed board 9 on the periphery of the semiconductor device from mold resin 4 via the copper plate 7. Thereby the effective heat dissipation area can be increased without adding heat dissipation fins to the semiconductor device, and the heat dissipation capability of the semiconductor device can be improved. Since the conventional package structure is applicable, package crack is not generated, and reliability can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a semiconductor device which has improved heat radiation performance for heat generation of a semiconductor element while suppressing generation of package cracks and cost increase.

[0002]

2. Description of the Related Art Recently, the number of high power consumption type semiconductor devices has increased rapidly. Since a high power consumption type semiconductor element is accompanied by heat generation of about 1 to several watts, a package in which the semiconductor element is mounted is required to have a structure capable of efficiently radiating heat generation and at low cost.

Conventionally, as a semiconductor device adopting such a heat dissipation structure, there is one shown in FIGS. 2 and 3, for example.

The semiconductor device shown in FIG. 2 has leads 3 of a lead frame, a metal plate 4 attached to the top of the leads 3 via an insulating adhesive 2, and a central portion of the lower surface of the metal plate 4. The semiconductor element 1 attached via the element adhesive 6, the bonding wire 11 connecting the semiconductor element 1 and the lead 3, and a part (outer lead portion) of the lead 3 are left, and the upper surface of the metal plate 4 is left. Is formed of a molding resin 5 that seals these so as to be exposed.

On the other hand, the semiconductor device shown in FIG. 3 is constructed by embedding a metal plate 4 inside a molding resin 5.

In the semiconductor device having such a structure, the heat generated in the semiconductor element 1 is transmitted through the metal plate 4 to the mold resin 5,
That is, heat is transferred to the entire package and is radiated by heat exchange between the package surface and air.

However, in any of the semiconductor devices, since a metal plate having low adhesion is embedded in a molding resin over a large area, cracks are likely to occur around the edge of the metal plate and the reliability is low. It has become.

Therefore, the structure of the package itself is not changed, and a radiating fin having a radiating area larger than that area is attached directly above the package through a heat conductive adhesive layer or the like.
As a result, a semiconductor device having improved heat dissipation effect has been proposed. According to this semiconductor device, since the structure of the package itself is not changed, that is, the metal plate is not arranged inside the mold resin, the heat dissipation can be improved without lowering the reliability of the package.

[0009]

However, according to the conventional semiconductor device having the radiation fins attached, since the radiation fins have a complicated uneven shape, the product cost becomes very large, and the manufacturing cost as a whole increases. There is the problem of becoming expensive. Further, since the thickness of the heat radiation fins is increased by the height of the heat radiation fins, there is a problem that the device becomes large and the mounting density on the printed circuit board becomes small.

Therefore, an object of the present invention is to provide a semiconductor device capable of improving heat dissipation while suppressing the occurrence of package cracks, cost increase, and size increase of the device.

[0011]

In view of the above problems, the present invention improves the heat dissipation while suppressing the generation of package cracks, the cost increase, and the size increase of the device. A semiconductor device provided with a conductive metal plate.

The above-mentioned good heat conductive metal plate is preferably made of a Cu-based alloy which has a good heat transfer coefficient and is advantageous in terms of cost. Both surfaces thereof are plated with Ni or Ni-Sn alloy. It is preferable that the first surface is adhered to the bottom surface of the mold resin and the second surface is adhered to the printed circuit board via the good heat conductive adhesives provided on both surfaces thereof. . With such a configuration, the heat generated from the semiconductor element can be transferred to the printed board, and the substantial heat radiation area can be increased in the existing package structure without attaching the heat radiation fin. As a result, it is possible to improve heat dissipation while suppressing an increase in cost and an increase in size of the device.

Here, the thickness of the good heat conductive metal plate is
In order to efficiently transfer the heat from the semiconductor element of the mold resin in the lateral direction, in the case of Cu-based material, it is necessary to be 0.05 mm or more, and ideally 0.2 mm is preferable. . It is desirable that the size is substantially equal to the size of the bottom surface of the mold resin, but if it is about twice as large as the semiconductor element, it can fulfill its role sufficiently.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor device of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a sectional structure of a semiconductor device according to an embodiment of the present invention. This semiconductor device applies an existing package structure, and includes a plurality of leads 3 of a lead frame, a tab portion 3a, and the tab portion 3.
a semiconductor element 1 mounted on a through an element adhesive 6
A bonding wire 11 for connecting the semiconductor element 1 and the inner lead portion of the lead 3; a mold resin 5 for covering a part of the lead 3 (outer lead portion) to cover them; and a bottom surface of the mold resin 5. It is composed of a copper plate 7.

The copper plate 7 has a thickness of 0.2 mm, and is plated with Ni on both sides thereof to provide adhesiveness. It is attached to the bottom.

As shown in the figure, the semiconductor device having such a structure can efficiently dissipate the heat generated by the semiconductor device 1 when it is fixed to the printed circuit board 9. That is, a good thermal conductive adhesive 7 is applied to the other surface of the copper plate 7, the copper plate 7 of the semiconductor device is adhered to the surface of the printed circuit board 9, and the leads 3 and the wiring 10 of the printed circuit board 9 are electrically connected and printed. When the semiconductor device is fixed to the substrate 9, heat generated from the semiconductor element 1 is transferred from the mold resin (entire package) 4 and the mold resin 4 to the printed board 9 around the semiconductor device through the copper plate 7. Therefore, the substantial heat dissipation area can be increased without adding a heat dissipation fin to the semiconductor device, and the heat dissipation of the semiconductor device can be improved. Moreover, since the existing package structure is applied, package cracks are not generated and reliability can be improved.

As described above, in the semiconductor device of the present invention, the heat generated by the semiconductor device is transferred to the printed circuit board through the metal plate having good thermal conductivity.
Further, the heat radiation area can be expanded without attaching the heat radiation fins, and as a result, the heat radiation performance can be improved while suppressing the cost increase and the size increase of the device.

[0019]

As described above, according to the semiconductor device of the present invention, since the good heat conductive metal plate is provided on the bottom surface of the molding resin, the package structure is not changed, and the heat radiation area is not attached to the heat radiation fin. The heat dissipation can be improved while suppressing the occurrence of package cracks, the cost increase, and the size increase of the device.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional semiconductor device.

FIG. 3 is a cross-sectional view showing another conventional semiconductor device.

[Explanation of symbols]

1 Semiconductor Device 2 Insulating Adhesive 3 Lead 4 Metal Plate 5 Mold Resin 6 Adhesive for Element 7 Copper Plate 8 Good Thermal Conductive Adhesive 9 Printed Circuit Board 10 Wiring 11 Bonding Wire

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeo Hagiya 3550 Kidayomachi, Tsuchiura City, Ibaraki Prefecture Hitachi Cable Ltd. System Materials Research Center

Claims (3)

[Claims] 1. A semiconductor device configured by wire-bonding a lead of a lead frame and a semiconductor element and sealing the semiconductor element with a molding resin while leaving a part of the lead, wherein a bottom surface of the molding resin is good. A semiconductor device comprising a heat conductive metal plate. 2. The semiconductor according to claim 1, wherein the metal plate with good thermal conductivity is made of a Cu-based alloy, and Ni plating or Ni—Sn alloy plating for imparting adhesiveness is applied to both surfaces of the metal plate. apparatus. 3. The good heat conductive metal plate has a first surface printed on the bottom surface of the mold resin and a second surface printed on the bottom surface of the mold resin via a good heat conductive adhesive provided on both surfaces thereof. 3. The semiconductor device according to claim 1, wherein each of the leads is adhered onto a board, and the lead is connected to a predetermined wiring of the printed board.